University of Minnesota August Starwatch

by Deane Morrison

August opens with Lammas, or the festival of loaves, an ancient Celtic celebration of the season’s first harvest. The August 1 holiday was one of four cross-quarter days falling midway between a solstice and an equinox.
The Celts divided the year into light and dark halves, with the switchovers happening on the dates we call Halloween and May Day. By this reckoning, Lammas marks the halfway point in the light half of the year, an occasion to rejoice in its bounty. Its opposite is Imbolc, or lamb’s milk, on February 2, which we now know as Groundhog Day.
As August goes by, starwatching gets better because now we notice the days shortening. Dominating the night is Jupiter, which on August 14 appears opposite the sun in the sky and so is visible all night. That moment, called opposition, happens whenever Earth passes between the sun and an outer planet, overtaking the planet in the orbital race. The king of planets doesn’t get very high, but its bright yellowish orb does spruce up a relatively star-poor area of the constellation Capricornus.
Saturn, soon to disappear over the western horizon, is also about to turn its rings edgewise to us. Anybody with a backyard telescope should get a look at the planet while the rings can still be seen. This may be hard the first week in August, however, thanks to interference from a bright moon.
In the morning sky, a brilliant Venus glides through the stars of Gemini. On the 17th, a waning crescent moon visits the lovely planet. To the upper right of Venus, Mars also makes its way through the star field. On the 16th, watch it hover between the horns of Taurus as the moon plays spectator.  
August’s full moon comes on the 5th, rising just half an hour before the actual moment of fullness. Algonquin Indians called this the full sturgeon moon, for the large Great Lakes fish that is easily caught this time of year. It was also known as the green corn moon. Set against a pale sky, it will be a very round, softly glowing beauty.
The beauty soon turns to beast, however. A waning moon will spoil much of the Perseid meteor shower, which peaks the night of August 11-12. Come to think of it, maybe Juliet was on to something when she urged Romeo not to swear by the fickle moon, “th’ inconstant moon, that monthly changes in her circle orb, lest that thy love prove likewise variable.”
The University of Minnesota offers public viewings of the night sky at its Morris, Duluth, and Twin Cities campuses. For more information and viewing schedules, see:
Morris, UMN 16-inch telescope schedule: cda.mrs.umn.edu/~kearnsk/Telescope/PubObs.htm
 Duluth, Marshall W. Alworth Planetarium: www.d.umn.edu/~planet
 Twin Cities, Department of Astronomy (during fall and spring semesters): www.astro.umn.edu/outreach/pubnight